DESTRUCTIVE DISTILLATION 41 



References : 



1. 1703 : 189-190. Destructive DistiUation of Wood. 



2. 1710 : 53-54. Illuminating Gas from Soft Coal. 



3. Circular 114. Forest Service, U. S. Dept. of Agriculture, 

 a. 1704 : 1G8-169. Destructive Distillation. 



6. 1706 : 188-189. Formation of Charcoal and Coke. 



c. 1708 : 82-83. Carbon from Other Compounds. 



d. 1709 : 374-377. Destructive Distillation. 



e. 1712:255. Destructive Distillation. 



Experiment 18. Destructive Distillation. 



Apparatus: Burner, test tube 6"xf", test-tube holder, 

 ordinary clay pipe. 



Materials : Chips of wood, soft coal, rice, sugar, starch. 



a. Place a few chips of wood in a test tube and heat it 

 gently. Notice what collects on the upper part of the tube. 

 Where did it come from ? Heat more strongly, moving the 

 tube through the flame so as to heat it uniformly. As soon 

 as the smoke becomes quite dense, light it. What does a 

 flame indicate always ? Continue to heat the wood, until no 

 more smoke comes off, and then examine the residue. What 

 is it? 



6. Repeat with rice, sugar, and starch. (Different pupils 

 may use different materials and compare notes, in order to 

 save time and material.) What are your conclusions in re- 

 gard to all of the substances which have been heated ? 



c. Place a few very small pieces of soft coal in the bowl of 

 a clay pipe, cover with wet clay (mud will do) and heat 

 strongly. The gas will burn at the mouthpiece for a con- 

 siderable time. After the gas ceases to be evolved, examine 

 the residue. Try to burn the residue. Remembering Para- 

 graph (e) in Experiment 3, draw your conclusions. 



